import QtQuick 2.0

Canvas {

    id: root
    width: 300; height: 300

    onPaint: {
        var ctx = getContext("2d")
        draw(ctx)
    }

    function draw(ctx){
        ctx.fillRect(0,0,300,300);
        for(var i = 0; i<3; i++)
        {
            for(var j=0;j<3;j++)
            {
                ctx.save();
                ctx.strokeStyle = "#9CFF00";
                ctx.translate(20+j*50,20+i*50);
                drawSpirograph(ctx,20*(j+2)/(j+1),-8*(i+3)/(i+1),10);
                ctx.restore();
            }

        }

    }

    function drawSpirograph(ctx,R,r,O)
    {
        var x1 = R-O;
        var y1 = 0;
        var i  = 1;
        ctx.beginPath();
        ctx.moveTo(x1,y1);
        do {
            if (i>20000) break;
            var x2 = (R+r)*Math.cos(i*Math.PI/72) - (r+O)*Math.cos(((R+r)/r)*(i*Math.PI/72))
            var y2 = (R+r)*Math.sin(i*Math.PI/72) - (r+O)*Math.sin(((R+r)/r)*(i*Math.PI/72))
            ctx.lineTo(x2,y2);
            x1 = x2;
            y1 = y2;
            i++;
        } while (x2 != R-O && y2 != 0 );
        ctx.stroke();

    }
}
